These tough, 2-ply, 3-mil Weston brand heavy-duty vacuum sealer bags (model 30-0008-W) are specially designed to be compatible with almost all brands of vacuum sealing machines. This product is a commercial-grade type of "bag on a roll" vacuum sealer bag; that is, it measures 8" x 50' (yes, fifty feet!) long, allowing you to cut your bags to any length you prefer.These rugged storage bags are superb for the freezing of fish, meats, and other food items and will virtually eliminate freezer burn. Storage in these bags helps keep contaminating moisture and air out of your stored foods much longer than other storage methods, extending the use date of stored foods up to six times as long as other types of non-vacuum methods. Foods sealed in these bags can be reheated by boiling while in the bag or they may be microwaved (providing you pierce the bag beforehand. These Weston bags are B.P.A.-free, dishwasher safe and reusable.